<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="./jquery-3.6.0.js"></script>
</head>
<body>
    <form action="" method="post" >
        <input type="checkbox" name="checked" id="">同意并接受注册协议<br>
        <button name="push">提交</button>
    </form>
    <script>
        console.log($('input').is(":checked"));
        console.log($('button'));
            $('button').click(function(){
               if ($('input').is(":checked")!=true){
                alert('不同意协议，我们将无法为您提供服务');
               }else{
                alert('提交成功');
               }
            })

    </script>
</body>
</html>